class AddLinksCounterCacheToCards < ActiveRecord::Migration def up add_column :cards, :links_count, :integer, default: 0, null: false PaperTrail.whodunnit = 1 Card.reset_column_information Card.find_each do |card| card.update_attribute(:links_count, card.links.count) end end def down remove_column :cards, :links_count end end